They were Africans, so they didn't really need closed in, but I did lock them in when they were younger. Now they have a pond and 20 acres and I couldn't tell you for sure where they sleep at night, but I think they scoot into the calving barn when its snowing.
Our ducks, my DH used 6 pallets, reinforced them to make them fully closed in, and made a nice box, but a door in it with a peephole/vent, and angled the pitch on the top to vent and roll water off. They snuggle in there quite nicely, but I wouldn't put more than 4 in there without doubling the size. It's like a giant doghouse with a latching door lol
Edit* and the ducks I DO lock up at night; they're wild mallards, but I have hungry coons and out if 13 ducklings, 7 survived to adulthood, so I keep them locked up tight now.
Edited by shortgrass - 10/27/15 at 5:03am